WorksheetsDetermining Absolute Age
Total questions: 10
Worksheet time: 6mins
Name
Class
Date
1.
How does absolute age differ from relative age?
a)
only absolute dating indicates which rock is older than another
b)
only absolute dating finds the age in years
c)
only relative dating finds the age in years
2.
About how long does it take for one varve to form?
a)
one year
b)
ten years
c)
one month
3.
What does one varve look like?
a)
a fine summer layer and a coarse winter layer on top
b)
a coarse summer layer with a fine winter layer below
c)
a coarse summer layer and a fine winter layer on top
4.
On what process does radiometric dating rely?
a)
radioactive decay
b)
counting varves
c)
sediment accumulation
5.
Suppose you had a sample containing 20 g of a parent isotope. After how many half lives would less than 2 g of the parent isotope remain?
a)
one
b)
two
c)
four
6.
After four half-lives, what fraction of the original parent isotopes remain?
a)
1/4
b)
1/16
c)
1/8
7.
How does the half-life of an isotope affect the accuracy of the radiometric dating method?
a)
if the rock is too young, there are no isotopes that can give its age accurately
b)
if the half-life is too long or too short for the rock to have parent and daughter material remaining, the age will not be accurate
c)
if the rock is too old, its age cannot be determined by any method
8.
Scientists find a rock that they think is about 250 million years old. Which of these dating methods could not be used to date the rock?
a)
potassium-argon dating
b)
uranium-lead dating
c)
radiocarbon dating
9.
What is half-life?
a)
it refers to the lifespan of a fossil
b)
the time required for half of a sample of radioactive isotope to form a daughter isotope
c)
the time required for daughter isotopes to become radioactive
10.
Suppose you have a shark's tooth that you think is about 15,000 years old. Would you use uranium-238 or carbon-14 to date the tooth and why?
a)
uranium-238 because it is more radioactive
b)
uranium-238 because it can be used for extremely old fossils
c)
carbon-14 because it is useful for organic matter less than 70,000 years old
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